We have found that inhibitors of cyanide-insensitive respiratory pathway induced male sterility in Brassica species, by treating to inflorescences and even seeds during germination. During germination, cyanide-insensitive respiration increased at first 6-8 hrs of imbibition. At this time, the treated seeds resulted a reduction in the number of fertile pollen grains at the flowering stage and some plants were observed as male sterile similar to cytoplasmic male sterility of Brassica species. Percent of cyanide-insensitive respiration to total respiration was lower on the young anther walls of the induced male sterile plants than control. It can be concluded that alternative respiration of sporophytic tissues in the young anthers might be essential for the development of pollen. This hypothesis was supported by an evidence that in vitro protein synthesis of mitochondria isolated from cauliflower was inhibited by the inhibitors of cyanide-insensitive respiration, but not from tumip, rather than enhanced by the inhibitors. This indicates that the function of mitochondria might be very specific for the tissues.The investigation of inheritance of the male sterility when crossed with normal pollens has continued to study F_2 progenies.